#include<iostream>
#include<string>
using namespace std;



class Solution {
public:
    bool isUnique(string astr)
    {
        int x = 0, n = astr.size();
        if (n > 26) return false;
        int flag = 0;
        for (auto i : astr)
        {
            int t = i - 'a';

            if (((x >> t) & 1) == 0)
            {

                x = x | (t << 1);
            }
            else return false;
        }
        return true;

    }
};


int main()
{
    class Solution().isUnique("dlkhgc");

    return 0;
}